Unscripted moments on stage can offer insight, clarity for voters during general election.

The power went out for 16 minutes at the start of the first 1976 presidential debate between Gerald Ford and Jimmy Carter. Frank Fahrenkopf remembers what happened next.

“They stood at their podiums and never said a word to each other,” Mr. Fahrenkopf said. “And when the lights came on they didn’t say a word to each other.”

These days, getting the candidates to talk to each other is Mr. Fahrenkopf’s job. The co-chair of the Commission on Presidential Debates called it one of the main goals of a general election debate.

Tuesday at the George Washington University, Mr. Fahrenkopf, his co-chair Mike McCurry and ABC News Chief Global Affairs Correspondent Martha Raddatz said the debates are critical to informing the public and giving voters an opportunity to measure candidates.

“I think you learn something from every debate,” said Ms. Raddatz, who moderated the 2012 vice presidential debate between Joe Biden and Paul Ryan. “I particularly think the general election debates are profoundly important because you are down to two people, or three, and at that point you really need to know where they stand on issues.”

‘A very different environment’

The three stressed the differences between the general election debates and the party primary versions, which in 2016 have at times devolved into a high school food fight. Republican Party front-runner Donald Trump has sparred with journalists and candidates alike since August from behind the debate podium.

The commission does not oversee the primary debates, which Mr. McCurry called “partisan exercises” run by the parties for the purpose of selecting a nominee.

“The primary debates are nothing like what we do in a general election debate,” said Mr. Fahrenkopf, a Terker Fellow at the School of Media and Public Affairs. “There are usually only about 600 to 1,000 people in the audience. They are warned ahead of time not to participate—you don’t have any clapping, cheering or booing. We have no ads. You’re not going to see a network’s name posted all over the screen.

“It’s a very different environment.”

Mr. McCurry, a former White House press secretary, said the goal is to create “a dignified experience.” He added a caveat to that, one that seemed aimed at Mr. Trump.

“It’s really going to be up to the candidates,” he said. “If we pick blowhards to be candidates that’s what we’ll end up with.”

Steven Roberts, right, and Frank Fahrenkopf discuss the presidential debates. "The American people want to like their president," Mr. Fahrenkopf said. "They want to have compassion for the candidate." (William Atkins/GW Today)

Comparing candidates side-by-side

The Commission on Presidential Debates selects the dates, sites, format and moderators for the general election debates. The candidates and their campaigns, Mr. Fahrenkopf and Mr. McCurry said, do not have influence in the matter.

“Now they’re not happy,” Mr. Fahrenkopf said. “They whine, they scream—they’re not happy with us anyway. But we choose them.”

“You want [the candidates] to be spontaneous,” she said. “You try to get them in a moment that offers clarity to the voters that they don’t get from ads or different kinds of debates.”

Personal trust

Voters want to like their president, Mr. Fahrenkopf said. But that connection can often be misconstrued, said Steven Roberts, the J.B. and M.C. Shapiro Professor of Media and Public Affairs.

“That issue often becomes, ‘Who would you like to have a beer with?’” he said. “I think that’s a vast oversimplification of what we’re saying. What we’re talking about is that element of personal trust. It’s an essential part of leadership. A debate gives perhaps a glimpse of that quality.

Voters are looking to create a bond with a president, Mr. McCurry said.

“We want someone who can do what Ronald Reagan did after the Challenger disaster, what Bill Clinton after the Murrah Building blew up in Oklahoma City and George Bush after 9/11,” he said. “We want someone who can use those skills that way, and that’s why we examine character and personality and likeability.”